Testimony of a Witness Given at a Former Trial (Former

Testimony of a witness given at a former trial (former testimony) :

A) is never admissible at a subsequent trial unless the same witness that testified at the first trial appears in court at the second trial for cross-examination.
B) is always admissible at a subsequent trial if the witness was under oath at the first trial.
C) even if considered hearsay, may be admitted at a subsequent trial if the witness making the statement is legitimately unavailable and the testimony at the former trial relates substantially to the same subject matter and is between the same parties.
D) is not admissible at a subsequent trial unless the witness is dead, and the testimony relates to the same subject matter.